public class MallardDuck extends Duck {
    public MallardDuck(String color, double heavy) {
        super(color, heavy);
    }

    public void setHeavy(int heavy) {
        this.heavy = heavy;
    }

    @Override
    public void fly() {
        System.out.println("绿头鸭在高空飞行");
    }

    @Override
    public void quack() {
        System.out.println("绿头鸭在欢快地呱呱叫");
    }
}